Multiple grain rocket for propelling underwater torpedoes



Nov. 7, 1950 w WALLACE l-:TAL 2,529,465

\ R. MULTIPLE GRAIN ROCKET FOR PROPELLING UNDERWATER TORPEDOES Filed Aug. 2, 1946 A 2 Sheets-Sheet 2 INVENToRs ROGER W. WALLAGE WLLM E. CLBRN BY I A TTORNEY Patented Nov. 7, 1950 UNITED sTATEs PATENT oFF/ice MULTIPLE GRAIN ROCKET ,Fon eRoBEL- 5 LING .UNDERWATER TORPEDQ-ES Roger W. Wallace, San Marino, and William Y Colburn, Inyokern, Calif., assignors ato the United States of America as represented bythe 'Secretary of the Navy Application August 2, 1946,1Serial No. 688,121

(Cl. `GIL-135.6)

The present 'invention relates generally to rocket `motors and -more specifically to a rocket `'motoradapted tolbemounted in the after body of atorpedo Ain place of the conventional torpedo turbine. I

An object ofthe invention-isto'provide arocket `motor of simple and rugged construction, particularly suited, for aircraft-launched, water-borne torpedoes, which is inherently capable of withstanding high deceleration `stresses occasioned by the torpedo striking the water athigh velocity.

Another object of the invention isto provide a rocket motor which `employs as its `propellant a comparatively fast burning explosive such as ballistite andlis so designed that a large quantty of such propellant Amay be employed with comparative safety.

'Another object ofthe invention is to provide a rocketmotor having a novel mounting arrangement for the propellant which in conjunction with simple but effective. means of inhibiting certain surfaces of the propellant grain, insures neutral or uniform burning'thereof for ai substantial pe` riod.

Astill-furtherobject of theinvention is to proi pear hereinafteninview reference is made to the accompanying drawings in which:

Fig; lis a longitudinal sectional view of a rocket motor 1 embodying the invention, taken on line I--I oflFig. 5.

Fig. 2 is a sectional view taken on line 2-2 l of Fig. 1. l l

` Fig. 3-'is a forward'end View of the rocket motor. Fig. 4 is an enlarged longitudinal sectional view of one ofthe propellant grain assemblies.

Fig. 5 is a sectional view taken on line 5-5 of Fig. l.

Fig; 6 isa perspective View of the system of bafllesfnthe water jacket surrounding the rocket housing.

The rocket motor herein described and illus- 'trated isintended tobe mounted in the after body of a torpedo in place of Vthesconventional torpedo .turbine andv associated mechanism; It is contemplated that parts of the rocket. motor, illustrated 4in the drawings, willV require modification tmtwithin :the streamlined form of the particular torpedo `in `which it will be mounted, but internally the motor will be essentially the same as theiconstruction shown` inl the drawings.. It is understood, too, that the use of the rocket motor eci . 2 herein described is not limited to torpedoesythe motor will have application to `all such `devices whiclrrequire a rocket motor of simple and` rugged construction and especially where high deceleration stresses may be encountered duringthe periodfof operation-of such devices.

The rocket-'motor housing comprises a heavywalled cylindrical shell I closed at its forward end a dome-shaped end member "2 which iswelded, or secured by e'quivalentmeans,` to the shell. The

`rearward end-of -the shell is closed by a domein to receive. the boltlshanks provides lateral sup#-- port for the bolts. An internal flange 'I isprovided at Ythe forward end of the shell I. Between the spacer bolts 6 and the flange 'I is positioned a propellant grain supporting frame comprising a forward bulkhead 8 and a rear bulkhead 9; these are separated by a central spacer tube I0. Each bulkhead is provided'with a central opening communicating withthe spacer tube I0 and in addition is provided with large peripheral openings surrounding the central opening. These peripheral openings are shown as six in number and communicate with propellant grain sleeves II which are heldbetween the bulkheads 8 and 9 in `the same manner as the central spacer tube I Il.

Each propellantgrain sleeve receives a single propellant grain I3, the cylindrical surface of which is provided with an inhibitor covering I4. For example, the propellant grain may beextruded ballistite and the inhibitor covering a wrapping or casing formed of cellulose `acetate suitably bonded or cemented to thelcylindrical surface of the propellant grain. l A retainer ring I5 is secured in one end of the sleeve I I as by `the weld IB which is machined ilat so that the sleeve may bear uniformly in a countersink provided aboutfeach of the openings in the forward bulkhead 8. A slidable retainer ring Il in the other end'of'the sleeve cooperates with the ring I5 to position the propellant grain in the sleeve.

Gaskets I8 are `provided between the retainer rings and the propellant grain.

As noted in Fig. 'l the forward bulkhead 8 rests on the fixed internal flange 1. Therear bulkheadil, also countersunk, cooperates with the forwardbulkhead 8 to secure the propellant `grain sleevesl I'in place and, in addition, serves to hold the slidable retainer rings Il in the sleeves` Ii `to secure the propellant grains I3 therein. After the spacer bolts 6 have been properly adjusted, assembly of the rear end member 3 on the cylindrical shell I causes the ends of the spacer bolts 6 to bear against the bulkhead 9 and thus serves not only to close the motor housing, but, in addition, to immovably position the motor frame, tubes and associated propellant grains within the housing.

The propellant grain I3 with its inhibitor covering I4 lits tightly within its sleeve II. The ends of the propellant grain are uninhibited so that both ends of the propellant grain can burn. The forward bulkhead 8, including the forward ends of the propellant grains, and the forward end member 2 define a forward combustion chamber I9. Similarly, the rear end member 3, the rear bulkhead 9 and the corresponding rear ends of the propellant grains define a rear combustion chamber 20. The forward combustion chamber is provided with an igniter 2I which is wired on the closure plug various means, old in the art, may be employed toY set olf the igniter charge. rIhe igniter isV aligned with the central spacer tube IIJ so that a portionof the ignition flame readily travels to the rear combustion chamber causing ignition of both ends of the propellant grains virtually simultaneously. The products of combustion from the forward combustion chamber I9 pass rearwardly through the central tube I0 and the products of combustion from both chambers are discharged through a discharge port 22 in the Yrear end member 3. The discharge port 22 communicates with a discharge tube 23 terminating in a nozzle 24.

Both the rocket motor housing as well as the discharge tube are surrounded by water jackets. Indi- Vidual water jackets 26 and 2l are provided, re-

spectively, at the forward and rear ends of the housing. Each is equipped with two internally threaded ports 28, one serving as an inlet the other as an outlet. A third water jacket 23 girdles the central body of the rocket motor; internally threaded inlet and outlet ports are similarly provided as well as a system of longitudinal and circular baffles, 3l and 32 respectively, which cooperate to direct the water in a circuitous path 33 within the jacket, as illustrated in Fig. 6. Tapped suspension pads 34 are positioned between the cylindrical shell I of the rocket motor housing and the outer wall of the central water jacket 29. These pads lend greater rigidity to the water jacket structure, cooperate with the baffles 3l and 32 to divert the water in the jacket through the circuitous path described above, and provide suspension means by which the rocketV motor may be mounted in the torpedo body. A lift loop 35 is also provided to facilitate handling of the rocket motor.

TheV discharge tube 23 is secured to the discharge port 22 by the bolts 36 and terminates in the nozzle 24. Both the discharge tube and nozzle are surrounded by the water jacket 31. The after end of the nozzle structure is secured to the after end of the water jacket wall by the bolts 38. Eositioning bolts 39 support and align the discharge tube 23 properly within the water jacket. Two internally threaded ports 40 communicate with the water jacket to serve as inlet and outlet ports.

When the present invention is employed in aircraft-launched, water-borne torpedoes, suitable means Vcan be provided to initiate operation of the rocket motor when the torpedo strikes the water. By reason of the fact that the propellant grains are inhibited, except for their two ends, their burning areas remain constant throughout the burning period. This insures uniform or neutral burning which is particularly desirable in rocket motors in order to avoid blowups or erratic operation or otherwise causing departures from predictable operation. Because of the fact that combustion takes place at both ends of the propellant grain, the propellant grain is not subjected to any appreciable pressure differential between its ends and, therefore, is not caused to move from its sleeve during the course of its burning. Also, because the ends only of the propellant grain burn, it is possible to use an otherwise fast burning propellant such as ballistite in a rocket motor which will functionfor several minutes. Still further, it has been found possible with the construction illustrated to employ a larger quantity of propellant than has been heretofore generally used. y From the foregoing description it will be seen that we have provided simple and rugged means for accomplishing all of the objects of the present invention. It will be understood that many changes may be made in the arrangement and detailsfof parts described without departing from the spirit of the invention as set forth in the accompanying claims. We, therefore, do not wish to be limited to the exact details shown and described as the preferred form only has been shown by way of illustration.

We claim:

l. A rocket motor comprising: a housing; a discharge tube and nozzle leading from said housing; a propellant grain supporting frame in said housing defining therewith a forward and a rear combustion chamber, said frame including a forward bulkhead and a rear bulkhead; tubes .extending between the said bulkheads, at least one ofsaid tubes defining a passageway betweensaid combustion chambers; and propellant grains in the remainder of said tubes;

2. A ,rocket motor'comprising: a housing; a discharge tube and nozzle leading from said housing; a propellant grain supporting frame in said housing defining therewith a forward and a rear combustion chamber, said frame including a forward bulkhead and a rear bulkhead; tubes lextending between said bulkheads, at least one of said tubes defining a passageway between said combustion chambers; and propellant grains in the remainder of said tubes, said propellant grains being inhibited except at their end surfaces which face said combustion chambers.

3. A rocket motor comprising: a housing; a propellant grain supporting frame positioned in said housing to define a forward and a rear combustion chamber, said frame including a forward bulkhead and a rear bulkhead; tubes extending between said bulkheads, at least one of said-tubes defining a passageway between said combustion chambers; Vsolid propellant grains fitted' in'the .remainder of said tubes, their axial endsonly being exposed to the combustion chambers; a discharge tube and nozzle leading from the rear combustion chamber; and an igniter in oneof said combustion chambers.

4. A rocket motor comprising: a'housing; ra propellant grain supportingfrarne positioned in said housing to define a forward and a rearlcombustion chamber, said frame including aV forward bulkhead and a rear bulkhead; tubes' extending between said bulkheads at least one of said tubes dening a passageway betweenv said combustion chambers; solid propellant graine fitted in the remainder of said tubes, said propellant grains being inhibited against burning except at their axial ends, which ends are exposed to the combustion chambers; a discharge tube and nozzle leading from the rear combustion chamber; and an igniter in one of said combustion chambers approximately aligned with said tube which denes a passageway between the combustion chambers.

5. A rocket motor comprising: a housing; a propellant grain supporting frame positioned in said housing to define a forward and a rear combustion chamber; tubes mounted in said supporting frame and extending between said combustion chambers, one of said tubes being centrally positioned and forming a passageway between the combustion chambers, the other tubes surrounding said central tube; solid cylindrical propellant grains having their cylindrical surfaces inhibited against burning and their axial extremities uninhibited, each of said grains fitting into one of said other tubes; a discharge tube and nozzle leading from the rear combustion chamber; and an igniter positioned in the forward combustion chamber and approximately aligned with said central tube.

6. A rocket motor comprising: a housing; a propellant grain supporting frame positioned in said housing to denne a forward and a rear combustion chamber, said frame including a forward bulkhead and a rear bulkhead; tubes extending between said bulkheads, one of said tubes being centrally positioned and forming a passageway between said combustion chambers, the

other tubes surrounding said central tube; solid cylindrical propellant grains having their cylindrical surfaces inhibited against burning and their axial extremities uninhibited, each of said grains tting into one of said other tubes; a discharge tube and nozzle leading from the rear combustion chamber; and an igniter positioned in the forward combustion chamber and approximately aligned with said central tube.

7. A rocket motor comprising: a housing; a propellant grain supporting frame positioned in said housing to define a forward and a rear combustion chamber; tubes mounted in said supporting frame and extending between said combustion chambers, at least one of said tubes defining a passageway between the combustion chambers; solid propellant grains fitted in the remainder of the tubes, their axial ends only being exposed to the combustion chambers; a discharge tube and nozzle leading from the rear combustion chamber; a water jacket surrounding said discharge tube and nozzle; and an igniter in one of said combustion chambers.

8. A rocket motor comprising: a housing; a propellant grain supporting frame positioned in said housing to define a forward and a rear combustion chamber; water jackets surrounding said combustion chambers; tubes mounted in said supporting frame and extending between said combustion chambers, at least one of said tubes defining a passageway between the combustion chambers; solid propellant grains tted in the remainder of the tubes, their axial ends only being exposed to the combustion chambers; a discharge tube and nozzle leading from the rear combustion chamber; and an igniter in one of said combustion chambers.

9. A rocket motor comprising: a housing; a,

water jacket surrounding said housing; a propellant grain supporting frame positioned in said housing to dene a forward and a rear combustion chamber, said frame including a forward bulkhead and a rear bulkhead; tubes extending between said bulkheads, at least one of said tubes dening a passageway between said combustion chambers; solid propellant grains tted in the remainder of the tubes, their axial ends only being exposed to the combustion chambers; a discharge tube and nozzle leading from the rearI combustion chamber; a water jacket surrounding said discharge tube and nozzle; and an igniter in one of said combustion chambers.

l0. A rocket motor comprising: a housing; a propellant grain supporting frame positioned in said housing to dene a forward and a rear combustion chamber, said frame including a forward bulkhead and a rear bulkhead; tubes extending between said bulkheads, at least one of said tubes defining a passageway between said combustion chambers; solid cylindrical propellant grains tted in the remainder of the tubes, said propellant grains having their cylindrical surfaces inhibited against burning and their axial extremities uninhibited; a discharge tube and nozzle leading from the rear combustion chamber; a water jacket surrounding said discharge tube and nozzle; and an igniter in one of said combustion chambers approximately aligned with said tube which defines a passageway between the combustion chambers.

1l. A rocket motor comprising: a housing; a propellant grain supporting frame positioned in said housing to define a forward and a rear combustion chamber, said frame including a forward bulkhead and a rear bulkhead; tubes extending between said bulkheads, at least one of said tubes defining a passageway between said combustion chambers; solid cylindrical propellant grains fitted in the remainder of the tubes, said propellant grains having their cylindrical surfaces inhibited against burning and their axial extremities uninhibited; water jackets surrounding said combustion chambers; a discharge tube and nozzle leading from the rear combustion chamber; and an igniter in one of said combustion chambers approximately aligned with said tube which denes a passageway between the combustion chambers.

12. A rocket motor comprising: a housing; a water jacket surrounding said housing; a propellant grain supporting frame positioned in said housing to denne a forward and a rear combustion chamber, said frame including a forward bulkhead and a rear bulkhead; tubes extending between said bulkheads, one of said tubes being centrally positioned and forming a passageway between said combustion chambers, the other tubes surrounding said central tube; solid cylindrical propellant grains having their cylindrical surfaces inhibited against burning and. their axial extremities uninhibited, each of said grains fitting into one of said other tubes; a discharge tube and nozzle leading from the rear combustion chamber; a water jacket surrounding said discharge tube and nozzle; and an igniter positioned in the forward combustion chamber and approximately aligned with said central tube.

ROGER W. WALLACE. WILLIAM E. COLBURN.

No references cited. 

